Chemistry - Salt Analysis Question with Solution | TestHub

Sulphur of organic compounds is detected by using sodium nitroprusside. With it sulphur forms a violet colour complex, called sodium thionitroprusside.

$\frac{{\mathrm{S}}^{2-}+{\mathrm{Na}}_2\left[\mathrm{Fe}\left(\mathrm{CN}{)}_5\right(\mathrm{NO}{)}^{+}\right]}{\mathrm{Sodium} \mathrm{nitroprusside}}\to \frac{{\mathrm{Na}}_4\left[\mathrm{Fe}\left(\mathrm{CN}{)}_5\right(\mathrm{NOS})\right]}{\mathrm{Violet} \mathrm{colour}}$